In recent years, domestic, commercial and industrial power consumption in many countries, particularly during the hours of peak power consumption, has been growing at a seemingly ever increasing rate. Because electric power utility companies are obligated to furnish power at levels sufficient to meet any customer requirement even if such levels occur infrequently or for only a few hours a day, the generating power capacity of the electric utility companies must be larger than the average power level requirements in order to provide the incremental power needed for periods of peak demand. Normally, and particularly in many countries in the summer time, peak power consumption occurs during several hours in the daytime, consumption levels falling to their so-called "off peak" levels during the night.
Electric utility companies conventionally operate generating plants having minimal costs and reasonably low operating costs, for example coal burning plants, to supply the base load and intermediate load of customers connected to the electric grid. Because peak power demands on electric utility companies occur only for relatively short periods of time, more expensive operating plants, such as gas turbines, which can be brought onto line quickly to furnish power are used during the short periods of peak demand. Consequently, the cost of peak power is normally several times larger than the cost of what is called baseload or "off-peak" power.
Recently, a system has been developed for providing peak power using a gas turbine wherein air necessary for the operation of the gas turbine is stored in underground caverns. At night, when relatively inexpensive power is available, an electrically driven air compressor is operated for compressing the air. During the day, when peak power is required, the compressed air is released from the caverns to the gas turbine for producing power via a coupled generator. In such a system, expensive caverns conventionally constructed underground are required to store the compressed gas.
It is therefore an object of the present invention to provide a new and improved method of and apparatus for producing electrical power during periods of peak power demand wherein the disadvantages as outlined including and related to the relatively large costs are reduced or substantially overcome.